<!DOCTYPE html>
<html lang="en">
<head>
  <meta charset="UTF-8">
  <meta http-equiv="X-UA-Compatible" content="IE=edge">
  <meta name="viewport" content="width=device-width, initial-scale=1.0">
  <title>Document</title>
</head>
<body>
  <script>
    let str = 'iloveyou';
    // let res = [...str].reverse().join('');

    // console.log(str.indexOf('ey'));
    // let res = str.repeat(3)

    // let res = str.slice(1, 5);
    let res = str.substr(1, 5);

    console.log(res);

  </script>
</body>
</html>